<script language="javascript">
    var btn = document.getElementById("agree");
    btn.innerHTML="请仔细阅读协议";
    var s = 10;
    var t = setInterval("settime()",600);
    function settime(){
        if(s!=1){
            s=s-1;
            agree.innerHTML="请仔细阅读协议"+s;
        }else{
        agree.innerHTML="<input type = 'button' value='同意'>";
        cleatInterval(t);
        }
    }
</script>

哥们，没明白？你要是秒数读取完以后直接跳转，还是需要点【同意】，如果点【同意】onclick就可以